Lava / magma ocean / Volcanic Worlds

Magma Ocean Waves And Thermal Variability On Lava Worlds

By Keith Cowing
Status Report
astro-ph.EP
January 25, 2026
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Magma Ocean Waves And Thermal Variability On Lava Worlds
Eigenfunctions describing tidal lava flows on a hemispherical dayside magma ocean. The nightside is masked in brown. Left half shows the scalar potential functions ϕr, computed by taking the real part of Eq. (8a) and plotted for n = 0, …, 4 and m = 0, …, n. Right half shows the stream functions ψr computed by taking the real part of Eq. (8b) and plotted for n = 1, …, 4 and m = 1, …, n. Bright and dark colors correspond to negative and positive values of the eigenfunctions, respectively. Left streamlines follow the tidal irrotational flow ∇ϕr, and right streamlines the tidal non-divergent flow ∇ψr × rˆ. — astro-ph.EP

Lava worlds are rocky planets with dayside skins made molten by stellar irradiation. Tidal heating on these shortest-period planets is more than skin deep.

We show how orbital eccentricities of just a few percent (within current observed bounds and maintained secularly by exterior companions) can create deep magma oceans. “Lava tidal waves” slosh across these oceans; we compute the multi-modal response of the ocean to tidal forcing, subject to a coastline at the day-night terminator and a parameterized viscous drag.

Wave interference produces a dayside heat map that is spatially irregular and highly time-variable; hotspots can wander both east and west of the substellar point, and thermal light curves can vary and spike aperiodically, from orbit to orbit and within an orbit. Heat deposited by tides is removed in steady state by a combination of fluid, mushy, and solid-state convection in the mantle. For Earth-sized planets with sub-day periods, the entire mantle may be tidally liquified.

Mohammad Farhat, Eugene Chiang

Comments: Submitted to AAS Journals
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2601.07080 [astro-ph.EP] (or arXiv:2601.07080v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2601.07080
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Submission history
From: Mohammad Farhat
[v1] Sun, 11 Jan 2026 22:07:11 UTC (44,672 KB)
https://arxiv.org/abs/2601.07080

Astrobiology, Exoplanet,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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